The present invention relates to a new and improved device for deforming cylindrical objects such as the rim of a wheel, two or more cylindrical bands are deformed sequentially to better work the metal and move it in a more precise and permanent relationship to the axis of rotation.
With respect to wheels, the prior art has utilized a single set of radially movable jaws that bear against the entire rim to deform all areas of the rim simultaneously. The dies used to deform the complete rim build up tremendous stresses in both the actuating mechanism and the rim; and the prior art utilizes large cams to develop the necessary jaw actuating forces.
I have discovered that advantages can be had when two sets of jaws are provided which can be actuated sequentially. In some instances, the deformation of one side of the rim may tend to bow the opposite side outwardly while the first side is being deformed. By utilizing overcenter devices to actuate the jaws which do the deforming, the jaws can be adjusted to be in the desired position when the devices are in top dead center. In addition, the overcenter devices automatically provide an increasing mechanical advantage as the deformation progresses. Preferably, the overcenter devices are in their inline position at the time that the rim is deformed to specifications, and a locking action is provided by holding them in line. By bringing one side of the rim to specification before deforming the other side, the other side may tend to rock outwardly before engaged by its set of jaws. The second set of jaws then deform the metal through a greater distance than would otherwise occur, and a better set occurs in the metal.
According to further aspects of the invention, a new and improved support table is provided which will support a workpiece placed in an approximate position where it can be engaged by the jaws and to thereafter allow the jaws to center the workpiece unopposed so that an unbalanced deformation of the wheel is not produced due to restraining forces of the support table. In addition, a resilient surfacing material is provided which will accommodate lateral movement into the table if such becomes necessary for the jaws to properly true the wheel.
Accordingly, one object of the invention is the provision of a new and improved radial truing device for cylindrical workpieces such as the rims of wheels and the like which truing device has at least two sets of jaws that are arranged side by side and which can sequentially deform adjacent areas of the workpieces.
Another object of the present invention is the provision of a new and improved device of the above described type in which the actuation of the jaws is accomplished by separate rings with overcenter devices positioned between the respective ring and its jaws, and which are constructed and arranged to move toward an overcenter position as the deformation of the workpiece progresses.
Another object of the present invention is the provision of a new and improved workpiece support table for use in conjunction with the jaws and which is constructed and arranged so that a workpiece can be placed thereon in an approximate position and which will allow the jaws to automatically center the workpiece without imparting restraining forces which will cause the deformation to be out of specification.
Further objects and advantages of the invention will become apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiments described with reference to the accompanying drawings forming a part of this specification.